Held one month after the 28 April 2019 general election, the Spanish Socialist Workers' Party (PSOE) of Prime Minister Pedro Sánchez scored a landslide victory—as well as the first win for the party in a European Parliament election in 15 years, also with Josep Borrell as its main candidate—by achieving 32.9% of the share and 20 seats, a result which allowed it to become the largest national delegation within the Progressive Alliance of Socialists and Democrats.

Citizens (Cs), which had integrated Union, Progress and Democracy (UPyD) within its lists ahead of the election, became the third most-voted party of the country, but at 12.2% and 7 seats it only slightly improved on the combined Cs–UPyD results in 2014.

Far-right Vox performed well below expectations after disappointing results for the party in the 2019 general election, scoring 6.2% of the share and 3 seats.

[a][4][5] Voting was on the basis of universal suffrage, which comprised all nationals and resident non-national European citizens over 18 years of age and in full enjoyment of their political rights.

In order to be entitled to run, parties, federations, coalitions and groupings of electors needed to secure the signature of at least 15,000 registered electors; this requirement could be lifted and replaced through the signature of at least 50 elected officials—deputies, senators, MEPs or members from the legislative assemblies of autonomous communities or from local city councils.